1. Field of the Invention
This invention relates to a unit panel for use in constructing a storage tank, and also to a storage tank thus constructed. More particularly, this invention relates to a unit panel for constructing a storage tank from which a liquid can be completely discharged without difficulty because the tank has an inclined bottom.
2. Description of the Prior Art
In general, containers such as tanks have a characteristic that the bigger the capacity of the container, the more difficult it is to build the container. Additionally, if big containers are initially prepared in a finished state, it may often be inconvenient to transport the completed containers to the location at which they are to be installed. Thus, it is convenient when constructing a tank having a large capacity to carry and assemble at the required location unit panels which have been prepared beforehand in a factory, instead of constructing the tank in its finished state from the beginning.
Thus, tanks have heretofore been constructed by connecting a number of unit panels beforehand prepared in a factory. To this end, a unit panel was used comprising a rectangular plane (a) with connecting rims (b) and (c) as shown in FIG. 1. The connecting rims consist of an inclined rim (b) and a perpendicular rim (c). The inclined rim (b) is provided at the periphery of plate (a) to extend at an angle of 135.degree. with respect to the plane of the plate (a). The rim (c) is provided at the outer edge of the inclined rim (b) at an angle of 135.degree. with respect to the plane of the inclined rim (b), and, accordingly, at an angle of 90.degree. with respect to the plane of the plate (a). The unit panel of FIG. 1 has the structure that the rectangular plate (a) is parallel to an open plane including, or defined by, edges of the perpendicular rims, and each of the perpendicular rims is in the form of a rectangle.
The unit panel of FIG. 1, however, has the disadvantage that, when several of the panels are assembled to form the bottom of a tank, it is difficult to discharge liquid completely from the tank because the bottom is flat and the liquid is hard to collect around an outlet as the amount of liquid is decreased.
It is a primary object, therefore, of the present invention to provide a unit panel for use in forming a tank, especially a bottom of a tank, which bottom is partly inclined, and from which the liquid can be completely discharged without difficulty.
The unit panel in the present invention is similar to the known unit panel in that the perpendicular rims are provided to stand at an angle of 90.degree. with respect to the open plane connecting edges of the perpendicular rims. However, the unit member of the present invention is difficult in that the plane of the plate, or top, is inclined with respect to said open plane.